linux/drivers/mmc/core/sdio_uart.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * SDIO UART/GPS driver
   4 *
   5 * Based on drivers/serial/8250.c and drivers/serial/serial_core.c
   6 * by Russell King.
   7 *
   8 * Author:      Nicolas Pitre
   9 * Created:     June 15, 2007
  10 * Copyright:   MontaVista Software, Inc.
  11 */
  12
  13/*
  14 * Note: Although this driver assumes a 16550A-like UART implementation,
  15 * it is not possible to leverage the common 8250/16550 driver, nor the
  16 * core UART infrastructure, as they assumes direct access to the hardware
  17 * registers, often under a spinlock.  This is not possible in the SDIO
  18 * context as SDIO access functions must be able to sleep.
  19 *
  20 * Because we need to lock the SDIO host to ensure an exclusive access to
  21 * the card, we simply rely on that lock to also prevent and serialize
  22 * concurrent access to the same port.
  23 */
  24
  25#include <linux/module.h>
  26#include <linux/init.h>
  27#include <linux/kernel.h>
  28#include <linux/sched.h>
  29#include <linux/mutex.h>
  30#include <linux/seq_file.h>
  31#include <linux/serial_reg.h>
  32#include <linux/circ_buf.h>
  33#include <linux/tty.h>
  34#include <linux/tty_flip.h>
  35#include <linux/kfifo.h>
  36#include <linux/slab.h>
  37
  38#include <linux/mmc/core.h>
  39#include <linux/mmc/card.h>
  40#include <linux/mmc/sdio_func.h>
  41#include <linux/mmc/sdio_ids.h>
  42
  43
  44#define UART_NR         8       /* Number of UARTs this driver can handle */
  45
  46
  47#define FIFO_SIZE       PAGE_SIZE
  48#define WAKEUP_CHARS    256
  49
  50struct uart_icount {
  51        __u32   cts;
  52        __u32   dsr;
  53        __u32   rng;
  54        __u32   dcd;
  55        __u32   rx;
  56        __u32   tx;
  57        __u32   frame;
  58        __u32   overrun;
  59        __u32   parity;
  60        __u32   brk;
  61};
  62
  63struct sdio_uart_port {
  64        struct tty_port         port;
  65        unsigned int            index;
  66        struct sdio_func        *func;
  67        struct mutex            func_lock;
  68        struct task_struct      *in_sdio_uart_irq;
  69        unsigned int            regs_offset;
  70        struct kfifo            xmit_fifo;
  71        spinlock_t              write_lock;
  72        struct uart_icount      icount;
  73        unsigned int            uartclk;
  74        unsigned int            mctrl;
  75        unsigned int            rx_mctrl;
  76        unsigned int            read_status_mask;
  77        unsigned int            ignore_status_mask;
  78        unsigned char           x_char;
  79        unsigned char           ier;
  80        unsigned char           lcr;
  81};
  82
  83static struct sdio_uart_port *sdio_uart_table[UART_NR];
  84static DEFINE_SPINLOCK(sdio_uart_table_lock);
  85
  86static int sdio_uart_add_port(struct sdio_uart_port *port)
  87{
  88        int index, ret = -EBUSY;
  89
  90        mutex_init(&port->func_lock);
  91        spin_lock_init(&port->write_lock);
  92        if (kfifo_alloc(&port->xmit_fifo, FIFO_SIZE, GFP_KERNEL))
  93                return -ENOMEM;
  94
  95        spin_lock(&sdio_uart_table_lock);
  96        for (index = 0; index < UART_NR; index++) {
  97                if (!sdio_uart_table[index]) {
  98                        port->index = index;
  99                        sdio_uart_table[index] = port;
 100                        ret = 0;
 101                        break;
 102                }
 103        }
 104        spin_unlock(&sdio_uart_table_lock);
 105
 106        return ret;
 107}
 108
 109static struct sdio_uart_port *sdio_uart_port_get(unsigned index)
 110{
 111        struct sdio_uart_port *port;
 112
 113        if (index >= UART_NR)
 114                return NULL;
 115
 116        spin_lock(&sdio_uart_table_lock);
 117        port = sdio_uart_table[index];
 118        if (port)
 119                tty_port_get(&port->port);
 120        spin_unlock(&sdio_uart_table_lock);
 121
 122        return port;
 123}
 124
 125static void sdio_uart_port_put(struct sdio_uart_port *port)
 126{
 127        tty_port_put(&port->port);
 128}
 129
 130static void sdio_uart_port_remove(struct sdio_uart_port *port)
 131{
 132        struct sdio_func *func;
 133
 134        spin_lock(&sdio_uart_table_lock);
 135        sdio_uart_table[port->index] = NULL;
 136        spin_unlock(&sdio_uart_table_lock);
 137
 138        /*
 139         * We're killing a port that potentially still is in use by
 140         * the tty layer. Be careful to prevent any further access
 141         * to the SDIO function and arrange for the tty layer to
 142         * give up on that port ASAP.
 143         * Beware: the lock ordering is critical.
 144         */
 145        mutex_lock(&port->port.mutex);
 146        mutex_lock(&port->func_lock);
 147        func = port->func;
 148        sdio_claim_host(func);
 149        port->func = NULL;
 150        mutex_unlock(&port->func_lock);
 151        /* tty_hangup is async so is this safe as is ?? */
 152        tty_port_tty_hangup(&port->port, false);
 153        mutex_unlock(&port->port.mutex);
 154        sdio_release_irq(func);
 155        sdio_disable_func(func);
 156        sdio_release_host(func);
 157
 158        sdio_uart_port_put(port);
 159}
 160
 161static int sdio_uart_claim_func(struct sdio_uart_port *port)
 162{
 163        mutex_lock(&port->func_lock);
 164        if (unlikely(!port->func)) {
 165                mutex_unlock(&port->func_lock);
 166                return -ENODEV;
 167        }
 168        if (likely(port->in_sdio_uart_irq != current))
 169                sdio_claim_host(port->func);
 170        mutex_unlock(&port->func_lock);
 171        return 0;
 172}
 173
 174static inline void sdio_uart_release_func(struct sdio_uart_port *port)
 175{
 176        if (likely(port->in_sdio_uart_irq != current))
 177                sdio_release_host(port->func);
 178}
 179
 180static inline unsigned int sdio_in(struct sdio_uart_port *port, int offset)
 181{
 182        unsigned char c;
 183        c = sdio_readb(port->func, port->regs_offset + offset, NULL);
 184        return c;
 185}
 186
 187static inline void sdio_out(struct sdio_uart_port *port, int offset, int value)
 188{
 189        sdio_writeb(port->func, value, port->regs_offset + offset, NULL);
 190}
 191
 192static unsigned int sdio_uart_get_mctrl(struct sdio_uart_port *port)
 193{
 194        unsigned char status;
 195        unsigned int ret;
 196
 197        /* FIXME: What stops this losing the delta bits and breaking
 198           sdio_uart_check_modem_status ? */
 199        status = sdio_in(port, UART_MSR);
 200
 201        ret = 0;
 202        if (status & UART_MSR_DCD)
 203                ret |= TIOCM_CAR;
 204        if (status & UART_MSR_RI)
 205                ret |= TIOCM_RNG;
 206        if (status & UART_MSR_DSR)
 207                ret |= TIOCM_DSR;
 208        if (status & UART_MSR_CTS)
 209                ret |= TIOCM_CTS;
 210        return ret;
 211}
 212
 213static void sdio_uart_write_mctrl(struct sdio_uart_port *port,
 214                                  unsigned int mctrl)
 215{
 216        unsigned char mcr = 0;
 217
 218        if (mctrl & TIOCM_RTS)
 219                mcr |= UART_MCR_RTS;
 220        if (mctrl & TIOCM_DTR)
 221                mcr |= UART_MCR_DTR;
 222        if (mctrl & TIOCM_OUT1)
 223                mcr |= UART_MCR_OUT1;
 224        if (mctrl & TIOCM_OUT2)
 225                mcr |= UART_MCR_OUT2;
 226        if (mctrl & TIOCM_LOOP)
 227                mcr |= UART_MCR_LOOP;
 228
 229        sdio_out(port, UART_MCR, mcr);
 230}
 231
 232static inline void sdio_uart_update_mctrl(struct sdio_uart_port *port,
 233                                          unsigned int set, unsigned int clear)
 234{
 235        unsigned int old;
 236
 237        old = port->mctrl;
 238        port->mctrl = (old & ~clear) | set;
 239        if (old != port->mctrl)
 240                sdio_uart_write_mctrl(port, port->mctrl);
 241}
 242
 243#define sdio_uart_set_mctrl(port, x)    sdio_uart_update_mctrl(port, x, 0)
 244#define sdio_uart_clear_mctrl(port, x)  sdio_uart_update_mctrl(port, 0, x)
 245
 246static void sdio_uart_change_speed(struct sdio_uart_port *port,
 247                                   struct ktermios *termios,
 248                                   struct ktermios *old)
 249{
 250        unsigned char cval, fcr = 0;
 251        unsigned int baud, quot;
 252
 253        switch (termios->c_cflag & CSIZE) {
 254        case CS5:
 255                cval = UART_LCR_WLEN5;
 256                break;
 257        case CS6:
 258                cval = UART_LCR_WLEN6;
 259                break;
 260        case CS7:
 261                cval = UART_LCR_WLEN7;
 262                break;
 263        default:
 264        case CS8:
 265                cval = UART_LCR_WLEN8;
 266                break;
 267        }
 268
 269        if (termios->c_cflag & CSTOPB)
 270                cval |= UART_LCR_STOP;
 271        if (termios->c_cflag & PARENB)
 272                cval |= UART_LCR_PARITY;
 273        if (!(termios->c_cflag & PARODD))
 274                cval |= UART_LCR_EPAR;
 275
 276        for (;;) {
 277                baud = tty_termios_baud_rate(termios);
 278                if (baud == 0)
 279                        baud = 9600;  /* Special case: B0 rate. */
 280                if (baud <= port->uartclk)
 281                        break;
 282                /*
 283                 * Oops, the quotient was zero.  Try again with the old
 284                 * baud rate if possible, otherwise default to 9600.
 285                 */
 286                termios->c_cflag &= ~CBAUD;
 287                if (old) {
 288                        termios->c_cflag |= old->c_cflag & CBAUD;
 289                        old = NULL;
 290                } else
 291                        termios->c_cflag |= B9600;
 292        }
 293        quot = (2 * port->uartclk + baud) / (2 * baud);
 294
 295        if (baud < 2400)
 296                fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
 297        else
 298                fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10;
 299
 300        port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
 301        if (termios->c_iflag & INPCK)
 302                port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
 303        if (termios->c_iflag & (BRKINT | PARMRK))
 304                port->read_status_mask |= UART_LSR_BI;
 305
 306        /*
 307         * Characters to ignore
 308         */
 309        port->ignore_status_mask = 0;
 310        if (termios->c_iflag & IGNPAR)
 311                port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
 312        if (termios->c_iflag & IGNBRK) {
 313                port->ignore_status_mask |= UART_LSR_BI;
 314                /*
 315                 * If we're ignoring parity and break indicators,
 316                 * ignore overruns too (for real raw support).
 317                 */
 318                if (termios->c_iflag & IGNPAR)
 319                        port->ignore_status_mask |= UART_LSR_OE;
 320        }
 321
 322        /*
 323         * ignore all characters if CREAD is not set
 324         */
 325        if ((termios->c_cflag & CREAD) == 0)
 326                port->ignore_status_mask |= UART_LSR_DR;
 327
 328        /*
 329         * CTS flow control flag and modem status interrupts
 330         */
 331        port->ier &= ~UART_IER_MSI;
 332        if ((termios->c_cflag & CRTSCTS) || !(termios->c_cflag & CLOCAL))
 333                port->ier |= UART_IER_MSI;
 334
 335        port->lcr = cval;
 336
 337        sdio_out(port, UART_IER, port->ier);
 338        sdio_out(port, UART_LCR, cval | UART_LCR_DLAB);
 339        sdio_out(port, UART_DLL, quot & 0xff);
 340        sdio_out(port, UART_DLM, quot >> 8);
 341        sdio_out(port, UART_LCR, cval);
 342        sdio_out(port, UART_FCR, fcr);
 343
 344        sdio_uart_write_mctrl(port, port->mctrl);
 345}
 346
 347static void sdio_uart_start_tx(struct sdio_uart_port *port)
 348{
 349        if (!(port->ier & UART_IER_THRI)) {
 350                port->ier |= UART_IER_THRI;
 351                sdio_out(port, UART_IER, port->ier);
 352        }
 353}
 354
 355static void sdio_uart_stop_tx(struct sdio_uart_port *port)
 356{
 357        if (port->ier & UART_IER_THRI) {
 358                port->ier &= ~UART_IER_THRI;
 359                sdio_out(port, UART_IER, port->ier);
 360        }
 361}
 362
 363static void sdio_uart_stop_rx(struct sdio_uart_port *port)
 364{
 365        port->ier &= ~UART_IER_RLSI;
 366        port->read_status_mask &= ~UART_LSR_DR;
 367        sdio_out(port, UART_IER, port->ier);
 368}
 369
 370static void sdio_uart_receive_chars(struct sdio_uart_port *port,
 371                                    unsigned int *status)
 372{
 373        unsigned int ch, flag;
 374        int max_count = 256;
 375
 376        do {
 377                ch = sdio_in(port, UART_RX);
 378                flag = TTY_NORMAL;
 379                port->icount.rx++;
 380
 381                if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
 382                                        UART_LSR_FE | UART_LSR_OE))) {
 383                        /*
 384                         * For statistics only
 385                         */
 386                        if (*status & UART_LSR_BI) {
 387                                *status &= ~(UART_LSR_FE | UART_LSR_PE);
 388                                port->icount.brk++;
 389                        } else if (*status & UART_LSR_PE)
 390                                port->icount.parity++;
 391                        else if (*status & UART_LSR_FE)
 392                                port->icount.frame++;
 393                        if (*status & UART_LSR_OE)
 394                                port->icount.overrun++;
 395
 396                        /*
 397                         * Mask off conditions which should be ignored.
 398                         */
 399                        *status &= port->read_status_mask;
 400                        if (*status & UART_LSR_BI)
 401                                flag = TTY_BREAK;
 402                        else if (*status & UART_LSR_PE)
 403                                flag = TTY_PARITY;
 404                        else if (*status & UART_LSR_FE)
 405                                flag = TTY_FRAME;
 406                }
 407
 408                if ((*status & port->ignore_status_mask & ~UART_LSR_OE) == 0)
 409                        tty_insert_flip_char(&port->port, ch, flag);
 410
 411                /*
 412                 * Overrun is special.  Since it's reported immediately,
 413                 * it doesn't affect the current character.
 414                 */
 415                if (*status & ~port->ignore_status_mask & UART_LSR_OE)
 416                        tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
 417
 418                *status = sdio_in(port, UART_LSR);
 419        } while ((*status & UART_LSR_DR) && (max_count-- > 0));
 420
 421        tty_flip_buffer_push(&port->port);
 422}
 423
 424static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
 425{
 426        struct kfifo *xmit = &port->xmit_fifo;
 427        int count;
 428        struct tty_struct *tty;
 429        u8 iobuf[16];
 430        int len;
 431
 432        if (port->x_char) {
 433                sdio_out(port, UART_TX, port->x_char);
 434                port->icount.tx++;
 435                port->x_char = 0;
 436                return;
 437        }
 438
 439        tty = tty_port_tty_get(&port->port);
 440
 441        if (tty == NULL || !kfifo_len(xmit) ||
 442                                tty->stopped || tty->hw_stopped) {
 443                sdio_uart_stop_tx(port);
 444                tty_kref_put(tty);
 445                return;
 446        }
 447
 448        len = kfifo_out_locked(xmit, iobuf, 16, &port->write_lock);
 449        for (count = 0; count < len; count++) {
 450                sdio_out(port, UART_TX, iobuf[count]);
 451                port->icount.tx++;
 452        }
 453
 454        len = kfifo_len(xmit);
 455        if (len < WAKEUP_CHARS) {
 456                tty_wakeup(tty);
 457                if (len == 0)
 458                        sdio_uart_stop_tx(port);
 459        }
 460        tty_kref_put(tty);
 461}
 462
 463static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
 464{
 465        int status;
 466        struct tty_struct *tty;
 467
 468        status = sdio_in(port, UART_MSR);
 469
 470        if ((status & UART_MSR_ANY_DELTA) == 0)
 471                return;
 472
 473        if (status & UART_MSR_TERI)
 474                port->icount.rng++;
 475        if (status & UART_MSR_DDSR)
 476                port->icount.dsr++;
 477        if (status & UART_MSR_DDCD) {
 478                port->icount.dcd++;
 479                /* DCD raise - wake for open */
 480                if (status & UART_MSR_DCD)
 481                        wake_up_interruptible(&port->port.open_wait);
 482                else {
 483                        /* DCD drop - hang up if tty attached */
 484                        tty_port_tty_hangup(&port->port, false);
 485                }
 486        }
 487        if (status & UART_MSR_DCTS) {
 488                port->icount.cts++;
 489                tty = tty_port_tty_get(&port->port);
 490                if (tty && C_CRTSCTS(tty)) {
 491                        int cts = (status & UART_MSR_CTS);
 492                        if (tty->hw_stopped) {
 493                                if (cts) {
 494                                        tty->hw_stopped = 0;
 495                                        sdio_uart_start_tx(port);
 496                                        tty_wakeup(tty);
 497                                }
 498                        } else {
 499                                if (!cts) {
 500                                        tty->hw_stopped = 1;
 501                                        sdio_uart_stop_tx(port);
 502                                }
 503                        }
 504                }
 505                tty_kref_put(tty);
 506        }
 507}
 508
 509/*
 510 * This handles the interrupt from one port.
 511 */
 512static void sdio_uart_irq(struct sdio_func *func)
 513{
 514        struct sdio_uart_port *port = sdio_get_drvdata(func);
 515        unsigned int iir, lsr;
 516
 517        /*
 518         * In a few places sdio_uart_irq() is called directly instead of
 519         * waiting for the actual interrupt to be raised and the SDIO IRQ
 520         * thread scheduled in order to reduce latency.  However, some
 521         * interaction with the tty core may end up calling us back
 522         * (serial echo, flow control, etc.) through those same places
 523         * causing undesirable effects.  Let's stop the recursion here.
 524         */
 525        if (unlikely(port->in_sdio_uart_irq == current))
 526                return;
 527
 528        iir = sdio_in(port, UART_IIR);
 529        if (iir & UART_IIR_NO_INT)
 530                return;
 531
 532        port->in_sdio_uart_irq = current;
 533        lsr = sdio_in(port, UART_LSR);
 534        if (lsr & UART_LSR_DR)
 535                sdio_uart_receive_chars(port, &lsr);
 536        sdio_uart_check_modem_status(port);
 537        if (lsr & UART_LSR_THRE)
 538                sdio_uart_transmit_chars(port);
 539        port->in_sdio_uart_irq = NULL;
 540}
 541
 542static int uart_carrier_raised(struct tty_port *tport)
 543{
 544        struct sdio_uart_port *port =
 545                        container_of(tport, struct sdio_uart_port, port);
 546        unsigned int ret = sdio_uart_claim_func(port);
 547        if (ret)        /* Missing hardware shouldn't block for carrier */
 548                return 1;
 549        ret = sdio_uart_get_mctrl(port);
 550        sdio_uart_release_func(port);
 551        if (ret & TIOCM_CAR)
 552                return 1;
 553        return 0;
 554}
 555
 556/**
 557 *      uart_dtr_rts            -        port helper to set uart signals
 558 *      @tport: tty port to be updated
 559 *      @onoff: set to turn on DTR/RTS
 560 *
 561 *      Called by the tty port helpers when the modem signals need to be
 562 *      adjusted during an open, close and hangup.
 563 */
 564
 565static void uart_dtr_rts(struct tty_port *tport, int onoff)
 566{
 567        struct sdio_uart_port *port =
 568                        container_of(tport, struct sdio_uart_port, port);
 569        int ret = sdio_uart_claim_func(port);
 570        if (ret)
 571                return;
 572        if (onoff == 0)
 573                sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
 574        else
 575                sdio_uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
 576        sdio_uart_release_func(port);
 577}
 578
 579/**
 580 *      sdio_uart_activate      -       start up hardware
 581 *      @tport: tty port to activate
 582 *      @tty: tty bound to this port
 583 *
 584 *      Activate a tty port. The port locking guarantees us this will be
 585 *      run exactly once per set of opens, and if successful will see the
 586 *      shutdown method run exactly once to match. Start up and shutdown are
 587 *      protected from each other by the internal locking and will not run
 588 *      at the same time even during a hangup event.
 589 *
 590 *      If we successfully start up the port we take an extra kref as we
 591 *      will keep it around until shutdown when the kref is dropped.
 592 */
 593
 594static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
 595{
 596        struct sdio_uart_port *port =
 597                        container_of(tport, struct sdio_uart_port, port);
 598        int ret;
 599
 600        /*
 601         * Set the TTY IO error marker - we will only clear this
 602         * once we have successfully opened the port.
 603         */
 604        set_bit(TTY_IO_ERROR, &tty->flags);
 605
 606        kfifo_reset(&port->xmit_fifo);
 607
 608        ret = sdio_uart_claim_func(port);
 609        if (ret)
 610                return ret;
 611        ret = sdio_enable_func(port->func);
 612        if (ret)
 613                goto err1;
 614        ret = sdio_claim_irq(port->func, sdio_uart_irq);
 615        if (ret)
 616                goto err2;
 617
 618        /*
 619         * Clear the FIFO buffers and disable them.
 620         * (they will be reenabled in sdio_change_speed())
 621         */
 622        sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
 623        sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
 624                       UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
 625        sdio_out(port, UART_FCR, 0);
 626
 627        /*
 628         * Clear the interrupt registers.
 629         */
 630        (void) sdio_in(port, UART_LSR);
 631        (void) sdio_in(port, UART_RX);
 632        (void) sdio_in(port, UART_IIR);
 633        (void) sdio_in(port, UART_MSR);
 634
 635        /*
 636         * Now, initialize the UART
 637         */
 638        sdio_out(port, UART_LCR, UART_LCR_WLEN8);
 639
 640        port->ier = UART_IER_RLSI|UART_IER_RDI|UART_IER_RTOIE|UART_IER_UUE;
 641        port->mctrl = TIOCM_OUT2;
 642
 643        sdio_uart_change_speed(port, &tty->termios, NULL);
 644
 645        if (C_BAUD(tty))
 646                sdio_uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
 647
 648        if (C_CRTSCTS(tty))
 649                if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS))
 650                        tty->hw_stopped = 1;
 651
 652        clear_bit(TTY_IO_ERROR, &tty->flags);
 653
 654        /* Kick the IRQ handler once while we're still holding the host lock */
 655        sdio_uart_irq(port->func);
 656
 657        sdio_uart_release_func(port);
 658        return 0;
 659
 660err2:
 661        sdio_disable_func(port->func);
 662err1:
 663        sdio_uart_release_func(port);
 664        return ret;
 665}
 666
 667/**
 668 *      sdio_uart_shutdown      -       stop hardware
 669 *      @tport: tty port to shut down
 670 *
 671 *      Deactivate a tty port. The port locking guarantees us this will be
 672 *      run only if a successful matching activate already ran. The two are
 673 *      protected from each other by the internal locking and will not run
 674 *      at the same time even during a hangup event.
 675 */
 676
 677static void sdio_uart_shutdown(struct tty_port *tport)
 678{
 679        struct sdio_uart_port *port =
 680                        container_of(tport, struct sdio_uart_port, port);
 681        int ret;
 682
 683        ret = sdio_uart_claim_func(port);
 684        if (ret)
 685                return;
 686
 687        sdio_uart_stop_rx(port);
 688
 689        /* Disable interrupts from this port */
 690        sdio_release_irq(port->func);
 691        port->ier = 0;
 692        sdio_out(port, UART_IER, 0);
 693
 694        sdio_uart_clear_mctrl(port, TIOCM_OUT2);
 695
 696        /* Disable break condition and FIFOs. */
 697        port->lcr &= ~UART_LCR_SBC;
 698        sdio_out(port, UART_LCR, port->lcr);
 699        sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
 700                                 UART_FCR_CLEAR_RCVR |
 701                                 UART_FCR_CLEAR_XMIT);
 702        sdio_out(port, UART_FCR, 0);
 703
 704        sdio_disable_func(port->func);
 705
 706        sdio_uart_release_func(port);
 707}
 708
 709static void sdio_uart_port_destroy(struct tty_port *tport)
 710{
 711        struct sdio_uart_port *port =
 712                container_of(tport, struct sdio_uart_port, port);
 713        kfifo_free(&port->xmit_fifo);
 714        kfree(port);
 715}
 716
 717/**
 718 *      sdio_uart_install       -       install method
 719 *      @driver: the driver in use (sdio_uart in our case)
 720 *      @tty: the tty being bound
 721 *
 722 *      Look up and bind the tty and the driver together. Initialize
 723 *      any needed private data (in our case the termios)
 724 */
 725
 726static int sdio_uart_install(struct tty_driver *driver, struct tty_struct *tty)
 727{
 728        int idx = tty->index;
 729        struct sdio_uart_port *port = sdio_uart_port_get(idx);
 730        int ret = tty_standard_install(driver, tty);
 731
 732        if (ret == 0)
 733                /* This is the ref sdio_uart_port get provided */
 734                tty->driver_data = port;
 735        else
 736                sdio_uart_port_put(port);
 737        return ret;
 738}
 739
 740/**
 741 *      sdio_uart_cleanup       -       called on the last tty kref drop
 742 *      @tty: the tty being destroyed
 743 *
 744 *      Called asynchronously when the last reference to the tty is dropped.
 745 *      We cannot destroy the tty->driver_data port kref until this point
 746 */
 747
 748static void sdio_uart_cleanup(struct tty_struct *tty)
 749{
 750        struct sdio_uart_port *port = tty->driver_data;
 751        tty->driver_data = NULL;        /* Bug trap */
 752        sdio_uart_port_put(port);
 753}
 754
 755/*
 756 *      Open/close/hangup is now entirely boilerplate
 757 */
 758
 759static int sdio_uart_open(struct tty_struct *tty, struct file *filp)
 760{
 761        struct sdio_uart_port *port = tty->driver_data;
 762        return tty_port_open(&port->port, tty, filp);
 763}
 764
 765static void sdio_uart_close(struct tty_struct *tty, struct file * filp)
 766{
 767        struct sdio_uart_port *port = tty->driver_data;
 768        tty_port_close(&port->port, tty, filp);
 769}
 770
 771static void sdio_uart_hangup(struct tty_struct *tty)
 772{
 773        struct sdio_uart_port *port = tty->driver_data;
 774        tty_port_hangup(&port->port);
 775}
 776
 777static int sdio_uart_write(struct tty_struct *tty, const unsigned char *buf,
 778                           int count)
 779{
 780        struct sdio_uart_port *port = tty->driver_data;
 781        int ret;
 782
 783        if (!port->func)
 784                return -ENODEV;
 785
 786        ret = kfifo_in_locked(&port->xmit_fifo, buf, count, &port->write_lock);
 787        if (!(port->ier & UART_IER_THRI)) {
 788                int err = sdio_uart_claim_func(port);
 789                if (!err) {
 790                        sdio_uart_start_tx(port);
 791                        sdio_uart_irq(port->func);
 792                        sdio_uart_release_func(port);
 793                } else
 794                        ret = err;
 795        }
 796
 797        return ret;
 798}
 799
 800static int sdio_uart_write_room(struct tty_struct *tty)
 801{
 802        struct sdio_uart_port *port = tty->driver_data;
 803        return FIFO_SIZE - kfifo_len(&port->xmit_fifo);
 804}
 805
 806static int sdio_uart_chars_in_buffer(struct tty_struct *tty)
 807{
 808        struct sdio_uart_port *port = tty->driver_data;
 809        return kfifo_len(&port->xmit_fifo);
 810}
 811
 812static void sdio_uart_send_xchar(struct tty_struct *tty, char ch)
 813{
 814        struct sdio_uart_port *port = tty->driver_data;
 815
 816        port->x_char = ch;
 817        if (ch && !(port->ier & UART_IER_THRI)) {
 818                if (sdio_uart_claim_func(port) != 0)
 819                        return;
 820                sdio_uart_start_tx(port);
 821                sdio_uart_irq(port->func);
 822                sdio_uart_release_func(port);
 823        }
 824}
 825
 826static void sdio_uart_throttle(struct tty_struct *tty)
 827{
 828        struct sdio_uart_port *port = tty->driver_data;
 829
 830        if (!I_IXOFF(tty) && !C_CRTSCTS(tty))
 831                return;
 832
 833        if (sdio_uart_claim_func(port) != 0)
 834                return;
 835
 836        if (I_IXOFF(tty)) {
 837                port->x_char = STOP_CHAR(tty);
 838                sdio_uart_start_tx(port);
 839        }
 840
 841        if (C_CRTSCTS(tty))
 842                sdio_uart_clear_mctrl(port, TIOCM_RTS);
 843
 844        sdio_uart_irq(port->func);
 845        sdio_uart_release_func(port);
 846}
 847
 848static void sdio_uart_unthrottle(struct tty_struct *tty)
 849{
 850        struct sdio_uart_port *port = tty->driver_data;
 851
 852        if (!I_IXOFF(tty) && !C_CRTSCTS(tty))
 853                return;
 854
 855        if (sdio_uart_claim_func(port) != 0)
 856                return;
 857
 858        if (I_IXOFF(tty)) {
 859                if (port->x_char) {
 860                        port->x_char = 0;
 861                } else {
 862                        port->x_char = START_CHAR(tty);
 863                        sdio_uart_start_tx(port);
 864                }
 865        }
 866
 867        if (C_CRTSCTS(tty))
 868                sdio_uart_set_mctrl(port, TIOCM_RTS);
 869
 870        sdio_uart_irq(port->func);
 871        sdio_uart_release_func(port);
 872}
 873
 874static void sdio_uart_set_termios(struct tty_struct *tty,
 875                                                struct ktermios *old_termios)
 876{
 877        struct sdio_uart_port *port = tty->driver_data;
 878        unsigned int cflag = tty->termios.c_cflag;
 879
 880        if (sdio_uart_claim_func(port) != 0)
 881                return;
 882
 883        sdio_uart_change_speed(port, &tty->termios, old_termios);
 884
 885        /* Handle transition to B0 status */
 886        if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
 887                sdio_uart_clear_mctrl(port, TIOCM_RTS | TIOCM_DTR);
 888
 889        /* Handle transition away from B0 status */
 890        if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
 891                unsigned int mask = TIOCM_DTR;
 892                if (!(cflag & CRTSCTS) || !tty_throttled(tty))
 893                        mask |= TIOCM_RTS;
 894                sdio_uart_set_mctrl(port, mask);
 895        }
 896
 897        /* Handle turning off CRTSCTS */
 898        if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
 899                tty->hw_stopped = 0;
 900                sdio_uart_start_tx(port);
 901        }
 902
 903        /* Handle turning on CRTSCTS */
 904        if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
 905                if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS)) {
 906                        tty->hw_stopped = 1;
 907                        sdio_uart_stop_tx(port);
 908                }
 909        }
 910
 911        sdio_uart_release_func(port);
 912}
 913
 914static int sdio_uart_break_ctl(struct tty_struct *tty, int break_state)
 915{
 916        struct sdio_uart_port *port = tty->driver_data;
 917        int result;
 918
 919        result = sdio_uart_claim_func(port);
 920        if (result != 0)
 921                return result;
 922
 923        if (break_state == -1)
 924                port->lcr |= UART_LCR_SBC;
 925        else
 926                port->lcr &= ~UART_LCR_SBC;
 927        sdio_out(port, UART_LCR, port->lcr);
 928
 929        sdio_uart_release_func(port);
 930        return 0;
 931}
 932
 933static int sdio_uart_tiocmget(struct tty_struct *tty)
 934{
 935        struct sdio_uart_port *port = tty->driver_data;
 936        int result;
 937
 938        result = sdio_uart_claim_func(port);
 939        if (!result) {
 940                result = port->mctrl | sdio_uart_get_mctrl(port);
 941                sdio_uart_release_func(port);
 942        }
 943
 944        return result;
 945}
 946
 947static int sdio_uart_tiocmset(struct tty_struct *tty,
 948                              unsigned int set, unsigned int clear)
 949{
 950        struct sdio_uart_port *port = tty->driver_data;
 951        int result;
 952
 953        result = sdio_uart_claim_func(port);
 954        if (!result) {
 955                sdio_uart_update_mctrl(port, set, clear);
 956                sdio_uart_release_func(port);
 957        }
 958
 959        return result;
 960}
 961
 962static int sdio_uart_proc_show(struct seq_file *m, void *v)
 963{
 964        int i;
 965
 966        seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n",
 967                       "", "", "");
 968        for (i = 0; i < UART_NR; i++) {
 969                struct sdio_uart_port *port = sdio_uart_port_get(i);
 970                if (port) {
 971                        seq_printf(m, "%d: uart:SDIO", i);
 972                        if (capable(CAP_SYS_ADMIN)) {
 973                                seq_printf(m, " tx:%d rx:%d",
 974                                              port->icount.tx, port->icount.rx);
 975                                if (port->icount.frame)
 976                                        seq_printf(m, " fe:%d",
 977                                                      port->icount.frame);
 978                                if (port->icount.parity)
 979                                        seq_printf(m, " pe:%d",
 980                                                      port->icount.parity);
 981                                if (port->icount.brk)
 982                                        seq_printf(m, " brk:%d",
 983                                                      port->icount.brk);
 984                                if (port->icount.overrun)
 985                                        seq_printf(m, " oe:%d",
 986                                                      port->icount.overrun);
 987                                if (port->icount.cts)
 988                                        seq_printf(m, " cts:%d",
 989                                                      port->icount.cts);
 990                                if (port->icount.dsr)
 991                                        seq_printf(m, " dsr:%d",
 992                                                      port->icount.dsr);
 993                                if (port->icount.rng)
 994                                        seq_printf(m, " rng:%d",
 995                                                      port->icount.rng);
 996                                if (port->icount.dcd)
 997                                        seq_printf(m, " dcd:%d",
 998                                                      port->icount.dcd);
 999                        }
1000                        sdio_uart_port_put(port);
1001                        seq_putc(m, '\n');
1002                }
1003        }
1004        return 0;
1005}
1006
1007static const struct tty_port_operations sdio_uart_port_ops = {
1008        .dtr_rts = uart_dtr_rts,
1009        .carrier_raised = uart_carrier_raised,
1010        .shutdown = sdio_uart_shutdown,
1011        .activate = sdio_uart_activate,
1012        .destruct = sdio_uart_port_destroy,
1013};
1014
1015static const struct tty_operations sdio_uart_ops = {
1016        .open                   = sdio_uart_open,
1017        .close                  = sdio_uart_close,
1018        .write                  = sdio_uart_write,
1019        .write_room             = sdio_uart_write_room,
1020        .chars_in_buffer        = sdio_uart_chars_in_buffer,
1021        .send_xchar             = sdio_uart_send_xchar,
1022        .throttle               = sdio_uart_throttle,
1023        .unthrottle             = sdio_uart_unthrottle,
1024        .set_termios            = sdio_uart_set_termios,
1025        .hangup                 = sdio_uart_hangup,
1026        .break_ctl              = sdio_uart_break_ctl,
1027        .tiocmget               = sdio_uart_tiocmget,
1028        .tiocmset               = sdio_uart_tiocmset,
1029        .install                = sdio_uart_install,
1030        .cleanup                = sdio_uart_cleanup,
1031        .proc_show              = sdio_uart_proc_show,
1032};
1033
1034static struct tty_driver *sdio_uart_tty_driver;
1035
1036static int sdio_uart_probe(struct sdio_func *func,
1037                           const struct sdio_device_id *id)
1038{
1039        struct sdio_uart_port *port;
1040        int ret;
1041
1042        port = kzalloc(sizeof(struct sdio_uart_port), GFP_KERNEL);
1043        if (!port)
1044                return -ENOMEM;
1045
1046        if (func->class == SDIO_CLASS_UART) {
1047                pr_warn("%s: need info on UART class basic setup\n",
1048                        sdio_func_id(func));
1049                kfree(port);
1050                return -ENOSYS;
1051        } else if (func->class == SDIO_CLASS_GPS) {
1052                /*
1053                 * We need tuple 0x91.  It contains SUBTPL_SIOREG
1054                 * and SUBTPL_RCVCAPS.
1055                 */
1056                struct sdio_func_tuple *tpl;
1057                for (tpl = func->tuples; tpl; tpl = tpl->next) {
1058                        if (tpl->code != 0x91)
1059                                continue;
1060                        if (tpl->size < 10)
1061                                continue;
1062                        if (tpl->data[1] == 0)  /* SUBTPL_SIOREG */
1063                                break;
1064                }
1065                if (!tpl) {
1066                        pr_warn("%s: can't find tuple 0x91 subtuple 0 (SUBTPL_SIOREG) for GPS class\n",
1067                                sdio_func_id(func));
1068                        kfree(port);
1069                        return -EINVAL;
1070                }
1071                pr_debug("%s: Register ID = 0x%02x, Exp ID = 0x%02x\n",
1072                       sdio_func_id(func), tpl->data[2], tpl->data[3]);
1073                port->regs_offset = (tpl->data[4] << 0) |
1074                                    (tpl->data[5] << 8) |
1075                                    (tpl->data[6] << 16);
1076                pr_debug("%s: regs offset = 0x%x\n",
1077                       sdio_func_id(func), port->regs_offset);
1078                port->uartclk = tpl->data[7] * 115200;
1079                if (port->uartclk == 0)
1080                        port->uartclk = 115200;
1081                pr_debug("%s: clk %d baudcode %u 4800-div %u\n",
1082                       sdio_func_id(func), port->uartclk,
1083                       tpl->data[7], tpl->data[8] | (tpl->data[9] << 8));
1084        } else {
1085                kfree(port);
1086                return -EINVAL;
1087        }
1088
1089        port->func = func;
1090        sdio_set_drvdata(func, port);
1091        tty_port_init(&port->port);
1092        port->port.ops = &sdio_uart_port_ops;
1093
1094        ret = sdio_uart_add_port(port);
1095        if (ret) {
1096                kfree(port);
1097        } else {
1098                struct device *dev;
1099                dev = tty_port_register_device(&port->port,
1100                                sdio_uart_tty_driver, port->index, &func->dev);
1101                if (IS_ERR(dev)) {
1102                        sdio_uart_port_remove(port);
1103                        ret = PTR_ERR(dev);
1104                }
1105        }
1106
1107        return ret;
1108}
1109
1110static void sdio_uart_remove(struct sdio_func *func)
1111{
1112        struct sdio_uart_port *port = sdio_get_drvdata(func);
1113
1114        tty_unregister_device(sdio_uart_tty_driver, port->index);
1115        sdio_uart_port_remove(port);
1116}
1117
1118static const struct sdio_device_id sdio_uart_ids[] = {
1119        { SDIO_DEVICE_CLASS(SDIO_CLASS_UART)            },
1120        { SDIO_DEVICE_CLASS(SDIO_CLASS_GPS)             },
1121        { /* end: all zeroes */                         },
1122};
1123
1124MODULE_DEVICE_TABLE(sdio, sdio_uart_ids);
1125
1126static struct sdio_driver sdio_uart_driver = {
1127        .probe          = sdio_uart_probe,
1128        .remove         = sdio_uart_remove,
1129        .name           = "sdio_uart",
1130        .id_table       = sdio_uart_ids,
1131};
1132
1133static int __init sdio_uart_init(void)
1134{
1135        int ret;
1136        struct tty_driver *tty_drv;
1137
1138        sdio_uart_tty_driver = tty_drv = alloc_tty_driver(UART_NR);
1139        if (!tty_drv)
1140                return -ENOMEM;
1141
1142        tty_drv->driver_name = "sdio_uart";
1143        tty_drv->name =   "ttySDIO";
1144        tty_drv->major = 0;  /* dynamically allocated */
1145        tty_drv->minor_start = 0;
1146        tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
1147        tty_drv->subtype = SERIAL_TYPE_NORMAL;
1148        tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
1149        tty_drv->init_termios = tty_std_termios;
1150        tty_drv->init_termios.c_cflag = B4800 | CS8 | CREAD | HUPCL | CLOCAL;
1151        tty_drv->init_termios.c_ispeed = 4800;
1152        tty_drv->init_termios.c_ospeed = 4800;
1153        tty_set_operations(tty_drv, &sdio_uart_ops);
1154
1155        ret = tty_register_driver(tty_drv);
1156        if (ret)
1157                goto err1;
1158
1159        ret = sdio_register_driver(&sdio_uart_driver);
1160        if (ret)
1161                goto err2;
1162
1163        return 0;
1164
1165err2:
1166        tty_unregister_driver(tty_drv);
1167err1:
1168        put_tty_driver(tty_drv);
1169        return ret;
1170}
1171
1172static void __exit sdio_uart_exit(void)
1173{
1174        sdio_unregister_driver(&sdio_uart_driver);
1175        tty_unregister_driver(sdio_uart_tty_driver);
1176        put_tty_driver(sdio_uart_tty_driver);
1177}
1178
1179module_init(sdio_uart_init);
1180module_exit(sdio_uart_exit);
1181
1182MODULE_AUTHOR("Nicolas Pitre");
1183MODULE_LICENSE("GPL");
1184